<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>background-clip</title>
  <style>
    .box1 {
      width: 400px;
      height: 400px;
      border: 1px solid black;
      background-image: url(../../images/bg03.jpg);
      background-repeat: no-repeat;
      /* background-size: auto; */
      /* background-size: 400px 400px; */
      /* background-size: 100%; */
      /* background-size: contain; */
      /* cover是最佳的 */
      background-size: cover;

    }


  </style>
</head>
<body>
  <div class="box1"></div>
  
</body>
</html>